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# Re: st: example about choice experiment datasheet

 From elisabetta capobianco To statalist@hsphsun2.harvard.edu Subject Re: st: example about choice experiment datasheet Date Thu, 6 Dec 2012 11:11:48 +0100

```Yes i know, I'm studying also your chapter about WTP because I'm
doing, for my phd work, a choice model to know WTP of public canteens
users and purchaising managers for a meat with environmental
charateristics.
I have ridden about to keep fixed price or as lognormal. But when I
take it fixed my WTP increases, and when I gen under lognormal I don't
have a realistic WTP.
I prefer the WTP of asclogit, it's more consistent with the price of
good in the real public market (for example organic meat), but
mixlogit seems to work better, so I would use mixlogit but keepping
price random under a normal (like letter a) output); Can I do it or
Have I necessarily keep it fixed or transform it in lognormal?

Thank you,
e

These are my outputs:               (bio=organic product; origine=
produced in the surrounding area; transport=transported  by truck with
low environment impact)

. asclogit  choice bio origine transport price, case(caseid)
alternatives (alt)  nocons
note: 58 cases (232 obs) dropped due to no positive outcome per case
note: variable origine has 634 cases that are not
alternative-specific: there is no within-case variability
note: variable transport has 499 cases that are not
alternative-specific: there is no within-case variability

Iteration 0:   log likelihood = -1877.1686
Iteration 1:   log likelihood = -1839.1132
Iteration 2:   log likelihood = -1835.7507
Iteration 3:   log likelihood = -1835.7428
Iteration 4:   log likelihood = -1835.7428

Alternative-specific conditional logit         Number of obs      =       8152
Case variable: caseid                          Number of cases    =       2038

Alternative variable: alt                      Alts per case: min =          4
avg =        4.0
max =          4

Wald chi2(4)    =    1301.46
Log likelihood = -1835.7428                       Prob > chi2     =     0.0000

choice            Coef.   Std. Err.      z          P>z     [95% Conf. Interval]

alt
bio             1.847154   .0646688    28.56   0.000     1.720406    1.973903
origine        1.370387   .0966343    14.18   0.000     1.180987    1.559787
transport    .9962071    .072193    13.80    0.000     .8547113    1.137703
price        -.1202996   .0101546   -11.85    0.000    -.1402023    -.100397

a)
mixlogit  choice, rand(  bio origine transport price) group( scen) id(
id) nrep(100)

Iteration 0:   log likelihood = -1799.8004  (not concave)
Iteration 1:   log likelihood = -1628.8724
Iteration 2:   log likelihood = -1608.0742  (not concave)
Iteration 3:   log likelihood =  -1598.731
Iteration 4:   log likelihood = -1595.4381
Iteration 5:   log likelihood = -1595.2625
Iteration 6:   log likelihood = -1595.2617
Iteration 7:   log likelihood = -1595.2617

Mixed logit model                                 Number of obs   =       8152
LR chi2(4)      =     480.96
Log likelihood = -1595.2617                       Prob > chi2     =     0.0000

choice           Coef.       Std. Err.      z        P>z     [95%
Conf. Interval]

Mean
bio             2.771951   .2267109    12.23   0.000     2.327606    3.216296
origine        1.851838   .1690234    10.96   0.000     1.520558    2.183117
transport    1.320959   .1392434     9.49   0.000     1.048047    1.593871
price        -.1610773   .0226479    -7.11   0.000    -.2054663   -.1166883

SD
bio             2.412158   .2464247     9.79   0.000     1.929175    2.895142
origine       .9607097   .1699508     5.65   0.000     .6276122    1.293807
transport    1.248339   .1627542     7.67   0.000     .9293467    1.567332
price          .1677565   .0195218     8.59   0.000     .1294944    .2060185

b)
mixlogit  choice price, rand(  bio origine transport) group( scen) id(
id) nrep(100)

Iteration 0:   log likelihood =  -1829.481  (not concave)
Iteration 1:   log likelihood = -1662.4878
Iteration 2:   log likelihood = -1660.0987  (not concave)
Iteration 3:   log likelihood = -1640.9778
Iteration 4:   log likelihood = -1636.7129
Iteration 5:   log likelihood = -1636.2943
Iteration 6:   log likelihood = -1636.2936
Iteration 7:   log likelihood = -1636.2936

Mixed logit model                                 Number of obs   =       8152
LR chi2(3)      =     398.90
Log likelihood = -1636.2936                       Prob > chi2     =     0.0000

choice          Coef.      Std. Err.      z          P>z     [95%
Conf. Interval]

Mean
price        -.1330338   .0113714   -11.70   0.000    -.1553213   -.1107463
bio            2.620523   .2089785    12.54   0.000     2.210933    3.030114
origine       1.778972   .1724494    10.32   0.000     1.440978    2.116967
transport    1.232111   .1309463     9.41   0.000     .9754614    1.488761

SD
bio            1.966898   .1712074    11.49   0.000     1.631338    2.302459
origine       1.085233   .1822183     5.96   0.000     .7280922    1.442375
transport    1.096156   .1394322     7.86   0.000     .8228738    1.369438

2012/12/5 Arne Risa Hole <arnehole@gmail.com>:
> Elisabetta
>
> The short answer is "yes, maybe". The long answer is long enough to
> write a whole book about it; see Hensher et al. which I mentioned
> earlier and http://elsa.berkeley.edu/books/choice2.html.
>
> Arne
>
>
>
> On 4 December 2012 12:12, elisabetta capobianco
> <elisabetta.capobianco@gmail.com> wrote:
>> Dear Arne,
>> the main concern about the conditional logit model is its assumption
>> of independence from
>> irrelevant alternatives (IIA).  This assumption implies that the
>> probability ratio of individuals
>> choosing between two alternatives does not depend on the availability
>> or attributes of the other
>> alternatives.
>> I have 4 alternatives for each choice set, so it's important to me to
>> surmount the IIA, and it's better using mixlogit than asclogit, isn't
>> it?
>>
>> Thank you,
>> elisabetta
>>
>>
>>
>> 2012/11/27 Arne Risa Hole <arnehole@gmail.com>:
>>> You are welcome. -mixlogit- implements the same model as -asclogit-
>>> but with random coefficients. You should make sure that you understand
>>> the differences between the models before moving on to -mixlogit-, as
>>> this is a more complicated model.
>>>
>>> Arne
>>>
>>> On 27 November 2012 05:31, elisabetta capobianco
>>> <elisabetta.capobianco@gmail.com> wrote:
>>>> Dear Arne,
>>>> you're my very helpful, thank you so much.
>>>> Now i'm trying to use mix logit, I've ridden your article. It seems to
>>>> be better than asclogit, because i have different alternatives on N
>>>> choices occasion. Is it more correct for my case, isn't it?
>>>>
>>>> Thank you!
>>>>
>>>> elisabetta
>>>>
>>>> 2012/11/26 Arne Risa Hole <arnehole@gmail.com>:
>>>>> This is to be expected; if you found it surprising you need to read
>>>>> the -asclogit- manual entry more carefully. Whether it's correct or
>>>>> not really depends on what you are trying to do. I would suggest that
>>>>> including socio-demographics in your model only makes sense if you
>>>>> interact them with the alternative-specific attributes, since your
>>>>> alternatives are unlabelled.
>>>>>
>>>>> Arne
>>>>>
>>>>> On 26 November 2012 10:43, elisabetta capobianco
>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>> Ok Arne,
>>>>>> now It's clear and I have had good results.
>>>>>> Just a doubt. When I put inside the socio-demographic variables, the
>>>>>> output has the four alternatives 1,2,3,4, even if I write nocons.
>>>>>> I don't understand the meaning of this output considering that I have
>>>>>> unlabelled alternatives.
>>>>>> Is however correct this result?
>>>>>>
>>>>>> Thank you,
>>>>>> Elisabetta
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> 2012/11/24 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>> Elisabetta,
>>>>>>>
>>>>>>> The "case" variable must a unique identifier for each choice. You can
>>>>>>> generate it like this
>>>>>>>
>>>>>>> egen caseid = group(id scenario)
>>>>>>>
>>>>>>> The "alt" variable should be coded 1,2,3,4,1,2,3,4 etc. (not
>>>>>>> 1,2,3,4,5,6,7,8,...).
>>>>>>>
>>>>>>> Arne
>>>>>>>
>>>>>>> On 24 November 2012 16:04, elisabetta capobianco
>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>> Thank you Arne, I have taken the book.
>>>>>>>> My problem is that I have 16 scenarios for id (n=131) with 4 different
>>>>>>>> alternatives for each scenario .
>>>>>>>> So in the dataset I have written for each id non 4 alternatives
>>>>>>>> (1,2,3,4) but 64 alternatives. Is it correct?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> id   scenario      alt
>>>>>>>> 1         1            1
>>>>>>>> 1         1            2
>>>>>>>> 1         1             3
>>>>>>>> 1         1            4
>>>>>>>> 1         2            5(or1?)
>>>>>>>> 1         2            6(or2?)
>>>>>>>> 1         2            7(or3?)
>>>>>>>> 1         2            8 (or4?)
>>>>>>>> 1         3            9(or1?)
>>>>>>>> .
>>>>>>>> .
>>>>>>>> .
>>>>>>>> .
>>>>>>>> .
>>>>>>>> 1         16           64
>>>>>>>> 2         1              1
>>>>>>>> .
>>>>>>>> .
>>>>>>>> And when I wrote:
>>>>>>>> asclogit choice organic price, case(id) alternatives(car) noconst
>>>>>>>>
>>>>>>>> case is id or scenario? I suppose scenario. But if is scenario I don't
>>>>>>>> know how to use id!
>>>>>>>> And alternatives are the 64 alternatives?
>>>>>>>>
>>>>>>>>
>>>>>>>> Thank you so much for your help.
>>>>>>>>
>>>>>>>> elisabetta
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>> Elisabetta
>>>>>>>>>
>>>>>>>>> I am fairly sure that you can use -asclogit- to do what you want. If
>>>>>>>>> you don't want alternative-specific constants you can use the
>>>>>>>>> -noconst- option. Modifying the example in the help-file slightly:
>>>>>>>>>
>>>>>>>>> webuse choice
>>>>>>>>> asclogit choice dealer, case(id) alternatives(car) noconst
>>>>>>>>>
>>>>>>>>> As you can see the only coefficient which is estimated in this case is
>>>>>>>>> the one for the dealer attribute, which is analogous to the organic
>>>>>>>>> and price attributes in your experiment. In your case the variable
>>>>>>>>> that identifies the alternatives for each case ("car" in the example)
>>>>>>>>> can simply take the values 1, 2, 3 and 4 since your alternatives are
>>>>>>>>> unlabelled.
>>>>>>>>>
>>>>>>>>> I also recommend taking a look at a basic choice modelling text before
>>>>>>>>> proceeding, such as
>>>>>>>>>
>>>>>>>>> Good luck!
>>>>>>>>>
>>>>>>>>> Arne
>>>>>>>>>
>>>>>>>>> On 23 November 2012 13:25, elisabetta capobianco
>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>> I think that asclogit is not the right comand for me.
>>>>>>>>>> Because I have 4 unlabeled alternatives, 16 diferrent scenarios with 4
>>>>>>>>>> alternatives for 131 individuals. So my indipendent viariables are the
>>>>>>>>>> attributes and dipendent variables the utility for each level of
>>>>>>>>>> attribute.
>>>>>>>>>> I need to know the importance of every level, not of alternatives.
>>>>>>>>>> Ex.:n=131
>>>>>>>>>> scenario 1)   A       B        C         D
>>>>>>>>>>      organic  org   no org   no org   org
>>>>>>>>>>      price       4         8         4         4
>>>>>>>>>> scenario 2)   A      B         C        D
>>>>>>>>>>     organic  no org  no org   org     no org
>>>>>>>>>>       price     12     16         8        8
>>>>>>>>>> .
>>>>>>>>>> .
>>>>>>>>>> .
>>>>>>>>>> Perhaps with mixlogit? Because the example is on a specific
>>>>>>>>>> alternative, car or bus.
>>>>>>>>>> I instead need to know the coefficient of attributes and levels.
>>>>>>>>>>
>>>>>>>>>> I don't know if I have explained well, I hope!
>>>>>>>>>>
>>>>>>>>>> e
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>>>> -help asclogit_postestimation-
>>>>>>>>>>>
>>>>>>>>>>> Arne
>>>>>>>>>>>
>>>>>>>>>>> On 23 November 2012 11:05, elisabetta capobianco
>>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>> Dear Arne,
>>>>>>>>>>>> i need to estimate the marginal effect of levels on attributes of my choice.
>>>>>>>>>>>> Is it possible?
>>>>>>>>>>>> es:
>>>>>>>>>>>> attribute   level
>>>>>>>>>>>> label        organic/not organic
>>>>>>>>>>>> prize        4/8
>>>>>>>>>>>>
>>>>>>>>>>>> I would know the utility for each level of each attribute.
>>>>>>>>>>>>
>>>>>>>>>>>> Thank you!
>>>>>>>>>>>> elisabetta
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> 2012/11/21 elisabetta capobianco <elisabetta.capobianco@gmail.com>:
>>>>>>>>>>>>> Thank you so much Arne!!!
>>>>>>>>>>>>> I'm creating the data set and then i'll try to run in Stata!
>>>>>>>>>>>>>
>>>>>>>>>>>>> Elisabetta
>>>>>>>>>>>>>
>>>>>>>>>>>>> 2012/11/20 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>>>>>>> Elisabetta
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> -mlogit- is not very useful to model data from choice experiments as
>>>>>>>>>>>>>> it does not allow alternative-specific explanatory variables.
>>>>>>>>>>>>>> -asclogit- requires your data to be in long form (one row per
>>>>>>>>>>>>>> alternative); see -help asclogit- and the first example in the paper I
>>>>>>>>>>>>>> mentioned in my last email.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Arne
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 20 November 2012 10:04, elisabetta capobianco
>>>>>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>>>>> Thank you Arne, I want to use asclogit and mlogit for my choice modelling.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 2012/11/19 Arne Risa Hole <arnehole@gmail.com>:
>>>>>>>>>>>>>>>> Elisabetta
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> As Jay says the correct data form depends on the estimation command
>>>>>>>>>>>>>>>> you are planning to use, so this is a very important piece of
>>>>>>>>>>>>>>>> information that you haven't given us. You may find the examples in
>>>>>>>>>>>>>>>> http://www.stata-journal.com/article.html?article=st0133 useful.
>>>>>>>>>>>>>>>> Generally speaking the best strategy is to import the data into Stata
>>>>>>>>>>>>>>>> and then use commands like -reshape- to convert the data into the form
>>>>>>>>>>>>>>>> you want, rather than trying to do this in Excel.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Arne
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> On 19 November 2012 15:51, elisabetta capobianco
>>>>>>>>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> I want to do a mixed logit, but I have found a data set on help file
>>>>>>>>>>>>>>>>>> with just one choice set. I have 16 choice sets and I don't know how
>>>>>>>>>>>>>>>>>> to fil the excel data set.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> 2012/11/18 JVerkuilen (Gmail) <jvverkuilen@gmail.com>:
>>>>>>>>>>>>>>>>>> > On Sun, Nov 18, 2012 at 4:11 AM, elisabetta capobianco
>>>>>>>>>>>>>>>>>> > <elisabetta.capobianco@gmail.com> wrote:
>>>>>>>>>>>>>>>>>> >> Hi, I'm new of statalist and stata!
>>>>>>>>>>>>>>>>>> >> I'm working on choice experiment about food preferences in schools.
>>>>>>>>>>>>>>>>>> >> I have 4 alternatives unlabelled, 4 attributes and 4 levels, 130
>>>>>>>>>>>>>>>>>> >> individuals.
>>>>>>>>>>>>>>>>>> >> I have the data base in excel, but before insheet the file in stata
>>>>>>>>>>>>>>>>>> >> i'm not sure that i have put the data in the right mode in the excel
>>>>>>>>>>>>>>>>>> >> file.
>>>>>>>>>>>>>>>>>> >> Have you got an example on a excel datasheet about choice modelling?
>>>>>>>>>>>>>>>>>> >> Just an example to understand how to organize my datasheet.
>>>>>>>>>>>>>>>>>> >
>>>>>>>>>>>>>>>>>> > It depends on what analysis you want to use. -clogit- and procedures
>>>>>>>>>>>>>>>>>> > like it that are using alternative-specific predictors use the same
>>>>>>>>>>>>>>>>>> > basic format, which is specified in the help file. You can see the
>>>>>>>>>>>>>>>>>> > example dataset there. Essentially it is a "long" format like
>>>>>>>>>>>>>>>>>> > person-period in a growth model with time-varying covariates.
>>>>>>>>>>>>>>>>>> > *
>>>>>>>>>>>>>>>>>> > *   For searches and help try:
>>>>>>>>>>>>>>>>>> > *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>>>>>> > *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>>>>>> > *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> *
>>>>>>>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> *
>>>>>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> *
>>>>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> *
>>>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> --
>>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>>>
>>>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>>>
>>>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>>>
>>>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>>>
>>>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>>>
>>>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>>>
>>>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>>>> che la sua diffusione
>>>>>>>>>>>>
>>>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>>>> prontamente avviso
>>>>>>>>>>>>
>>>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>>>
>>>>>>>>>>>> *
>>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>>
>>>>>>>>>>> *
>>>>>>>>>>> *   For searches and help try:
>>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>>>> eventuali documenti allegati
>>>>>>>>>>
>>>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>>>> destinatario. Nel caso
>>>>>>>>>>
>>>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>>>> che la sua diffusione
>>>>>>>>>>
>>>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>>>> prontamente avviso
>>>>>>>>>>
>>>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>>>
>>>>>>>>>> *
>>>>>>>>>> *   For searches and help try:
>>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>>
>>>>>>>>> *
>>>>>>>>> *   For searches and help try:
>>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>>>> eventuali documenti allegati
>>>>>>>>
>>>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>>>> destinatario. Nel caso
>>>>>>>>
>>>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>>>> che la sua diffusione
>>>>>>>>
>>>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>>>> prontamente avviso
>>>>>>>>
>>>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>>>
>>>>>>>> *
>>>>>>>> *   For searches and help try:
>>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>>
>>>>>>> *
>>>>>>> *   For searches and help try:
>>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>>>
>>>>>>
>>>>>>
>>>>>>           Le informazioni contenute in questa comunicazione e gli
>>>>>> eventuali documenti allegati
>>>>>>
>>>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>>>> destinatario. Nel caso
>>>>>>
>>>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>>>> che la sua diffusione
>>>>>>
>>>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>>>> prontamente avviso
>>>>>>
>>>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>>>
>>>>>> *
>>>>>> *   For searches and help try:
>>>>>> *   http://www.stata.com/help.cgi?search
>>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>>
>>>>> *
>>>>> *   For searches and help try:
>>>>> *   http://www.stata.com/help.cgi?search
>>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>
>>>>
>>>>
>>>> --
>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>>>
>>>>
>>>>
>>>>           Le informazioni contenute in questa comunicazione e gli
>>>> eventuali documenti allegati
>>>>
>>>>           hanno carattere confidenziale e sono a uso esclusivo del
>>>> destinatario. Nel caso
>>>>
>>>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>>>> che la sua diffusione
>>>>
>>>>           e riproduzione è contraria alla legge e prego di darmi
>>>> prontamente avviso
>>>>
>>>>           e di cancellare quanto ricevuto. Grazie.
>>>>
>>>> *
>>>> *   For searches and help try:
>>>> *   http://www.stata.com/help.cgi?search
>>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>
>>> *
>>> *   For searches and help try:
>>> *   http://www.stata.com/help.cgi?search
>>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>>> *   http://www.ats.ucla.edu/stat/stata/
>>
>>
>>
>> --
>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail
>>
>>
>>
>>           Le informazioni contenute in questa comunicazione e gli
>> eventuali documenti allegati
>>
>>           hanno carattere confidenziale e sono a uso esclusivo del
>> destinatario. Nel caso
>>
>>           questa comunicazione Vi sia pervenuta per errore, Vi informo
>> che la sua diffusione
>>
>>           e riproduzione è contraria alla legge e prego di darmi
>> prontamente avviso
>>
>>           e di cancellare quanto ricevuto. Grazie.
>>
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>> *   http://www.ats.ucla.edu/stat/stata/
>
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/faqs/resources/statalist-faq/
> *   http://www.ats.ucla.edu/stat/stata/

--
Rispetta l'ambiente: se non ti è necessario, non stampare questa mail

Le informazioni contenute in questa comunicazione e gli
eventuali documenti allegati

hanno carattere confidenziale e sono a uso esclusivo del
destinatario. Nel caso

questa comunicazione Vi sia pervenuta per errore, Vi informo
che la sua diffusione

e riproduzione è contraria alla legge e prego di darmi
prontamente avviso

e di cancellare quanto ricevuto. Grazie.

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/
```